Benzimidazole derivatives intended for inhibiting gastric acid secretion are disclosed in numerous patent documents. Among these can be mentioned GB No. 1 500 043, GB No. 1 525 958, U.S. Pat. Nos. 4 182 766, 4 255 431, 4 599 347, 4 555 518, 4 727 150, 4 628 098, EP No. 208 452 and Derwent abstract 87-29449/42. Benzimidazole derivatives proposed for use in the treatment or prevention of special gastrointestinal inflammatory diseases are disclosed in U.S. Pat. No. 4 539 465.